Bacterial alginates: from biosynthesis to applications
- First Online:
- 1.4k Downloads
Alginate is a polysaccharide belonging to the family of linear (unbranched), non-repeating copolymers, consisting of variable amounts of β-d-mannuronic acid and its C5-epimer α- l-guluronic acid linked via β-1,4-glycosidic bonds. Like DNA, alginate is a negatively charged polymer, imparting material properties ranging from viscous solutions to gel-like structures in the presence of divalent cations. Bacterial alginates are synthesized by only two bacterial genera, Pseudomonas and Azotobacter, and have been extensively studied over the last 40 years. While primarily synthesized in form of polymannuronic acid, alginate undergoes chemical modifications comprising acetylation and epimerization, which occurs during periplasmic transfer and before final export through the outer membrane. Alginate with its unique material properties and characteristics has been increasingly considered as biomaterial for medical applications. The genetic modification of alginate producing microorganisms could enable biotechnological production of new alginates with unique, tailor-made properties, suitable for medical and industrial applications.
Keywordsalginate alginate polymerisation alginate secretion Azotobacter biomaterial biopolymer guluronic acid mannuronic acid Pseudomonas
Unable to display preview. Download preview PDF.
- Bakkevig K, Sletta H, Gimmestad M, Aune R, Ertesvåg H, Degnes K, Christensen BE, Ellingsen TE, Valla S (2005) Role of the Pseudomonas fluorescens alginate lyase (AlgL) in clearing the periplasm of alginates not exported to the extracellular environment. J Bacteriol 187(24):8375–8384PubMedCrossRefGoogle Scholar
- Gacesa P, Russell NJ (1990) The structure and property of alginate. In: Pseudomonas infection and alginates. London, Chapman & Hall, pp 29–49Google Scholar
- Gimmestad M, Sletta H, Ertesvåg H, Bakkevig K, Jain S, Suh S-J, Skjåk-Bræk G, Ellingsen TE, Ohman DE, Valla S (2003) The Pseudomonas fluorescens AlgG protein, but not its mannuronan C-5-epimerase activity, is needed for alginate polymer formation. J Bacteriol 185:3515–3523PubMedCrossRefGoogle Scholar
- May TB, Shinabarger D, Boyd A, Chakrabarty AM (1994) Identification of amino acid residues involved in the activity of phosphomannose isomerase-guanosine 5′-diphospho-d-mannose pyrophosphorylase. A bifunctional enzyme in the alginate biosynthetic pathway of Pseudomonas aeruginosa. J Biol Chem 269(7):4872–4877PubMedGoogle Scholar
- Rehm BHA (2005) Biosynthesis and applications of alginates. In: Francis T (ed) Encyclopedia of biomaterials and biomedical engineering, vol 1, pp 1–9Google Scholar
- Rehm BHA, Boheim G, Tommassen J, Winkler UK (1994a) Overexpression of algE in Escherichia coli: subcellular localization, purification, and ion channel properties. J Bacteriol 176:5639–5647Google Scholar
- Remminghorst U, Rehm BHA (2006a) Alg44, a unique protein required for alginate biosynthesis in Pseudomonas aeruginosa. FEBS Lett (in press)Google Scholar
- Salzig M, Rehm BHA (2006) Microbial production of alginates: self assembly and applications. In: Rehm BHA (ed) Microbial bionanotechnology: biological self-assembly systems and biopolymer-based nanostructures. Horizon Bioscience, pp 125–152Google Scholar